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BMW i4 battery degradation: SoH by mileage, life expectancy and warranty

Published 2026-10-30 · Last updated 2026-10-30 · based on 24 sourced i4 data points and 36 sources

How much battery capacity does a used BMW i4 lose, and how long will the battery last? This page brings together AVILOO's results from 7,252 tested i4s, 21 UK dealer battery certificates, the battery recalls and BMW's UK warranty terms – with what the data can and can't tell you.

All figures with method and date: used BMW i4 battery data. Going to a viewing? Make a printable list of questions for the seller.

1. How much do i4 batteries degrade?

AVILOO medians are the middle value of tested cars at that mileage; the band shows where the central 99% of cars fall. All i4 battery sizes are grouped.

• The median drops by 1.3 points between 50,000 and 100,000 km and by 0.7 points between 100,000 and 150,000 km. The medians come from different cars at each mileage, so read this as a snapshot, not one car's history.
• The spread matters more than the median: at 150,000 km the central 99% of cars ran from 87.5% to 96.9%. A good average doesn't guarantee a good car.
• As a rule of thumb for all EVs, ADAC expects at least 92% at 50,000 km, 88% at 100,000 km, 84% at 150,000 km, 80% at 200,000 km (ADAC).
• Compare the i4 with other models on the battery degradation chart, or get an estimate for a specific car with the battery health estimator.

2. How long will the battery last?

Nobody has measured an i4 battery to the end of its life yet: EV Database lists the i4 as available to order in the UK from November 2021 (EV Database). The highest mileage in AVILOO's report is 150,000 km (≈93,000 miles), where the median i4 was at 93.6% and the lowest 0.5% of tested cars were at about 87.5% – still well above the 70% level that BMW's warranty treats as excessive loss. The UK dealer certificates in our data only go up to 69,950 km.

We don't project those figures beyond the mileages that were measured. What you can say for a used i4 today: the data so far shows slow loss, and no i4 is yet past the 8 years of the battery warranty (the 100,000-mile limit still applies).

3. Which battery does the car have?

EV Database listings, checked 2026-10-30. All are listed as NMC with prismatic cells. EV Database lists the same 83.9 kWh nominal pack with a slightly higher usable figure from June 2024.

The eDrive35 has a smaller battery than the eDrive40 and M50. The dealer certificates below show it, so compare a car with the same version. AVILOO's medians group all versions.

4. Check the battery recalls

When we downloaded DVSA's recall file on 2026-10-30, it listed these high-voltage battery recalls for the i4 (DVSA). Where a recall also covered other BMW models, the number is for the whole campaign:

• R/2022/330, 21 October 2022: during the supplier's cell production the cathode plate may have been damaged and a broken piece may have got inside a cell. BMW strongly recommended not charging or using the car until the repair, and parking it outdoors away from buildings. The defective cell modules are replaced. 211 vehicles (i4 and iX); i4s built 13 July 2021 – 7 October 2022.
• R/2025/274, 23 July 2025: a battery module frame may have been made with too much force; with cell swelling this could lead to failure and a possible thermal event. Modules replaced. 2 i4s built 3 June 2022 – 7 June 2023.
• R/2024/211, 29 February 2024: faulty cell modules could cause a battery malfunction; modules replaced. 1 i4 built 13 December 2023.
• R/2023/133, 8 May 2023: a cable bridge in the cell supervision circuit (CSC) may not have been fitted properly; the CSC inside the battery is replaced. 28 vehicles across four BMW models; i4s built 8 April – 15 November 2022.
• R/2022/020, 26 January 2022: crash pads may not have been fitted to the high-voltage battery; inspected and retrofitted. 133 vehicles built 15 September – 29 November 2021.
• R/2023/235, 1 August 2023: a damaged Combined Charging Unit (the charging electronics, not the battery) may have been fitted; replaced. 27 vehicles; i4s built 21 June – 4 July 2022.

Run the free GOV.UK recall check on the registration (GOV.UK) and ask for proof that any recall work was done. A car that had cell modules replaced may show a different battery reading from before the repair.

5. Check the battery warranty

BMW UK: high-voltage battery covered against defects or degradation for 8 years from first registration or 100,000 miles, whichever comes first. BMW's July 2026 UK warranty handbook sets the degradation claim at capacity below 70% of new, measured by a BMW Authorised Repairer; the handbook is issued with the car, so check the one for the specific car. (BMW, BMW UK, checked 2026-10-30)

• BMW says the battery status shown in the car is only approximate; a claim is decided on the authorised repairer's measurement. A repaired or replaced battery may not be as new but will have at least 70% usable capacity (BMW).
• Conditions in the handbook include: servicing to BMW's schedule (you may need proof), installing remote software updates when notified, not leaving the car at 0% with no range for more than 14 days, and high-voltage repairs only by an authorised repairer. Ask for the service history and whether software updates are current.
• BMW Approved Used cars come with at least 12 months' used-car warranty (BMW UK).
• Our battery warranty checker works out the time and mileage left (UK terms (BMW handbook, July 2026): 8 years / 100,000 miles, below 70%).

6. Get a battery reading and compare it

An independent test such as AVILOO measures the battery with its own method (AVILOO GmbH); options and prices are on our UK battery test comparison. On the 21 UK dealer AVILOO certificates in our data, the car's own (BMS) figure, shown as a whole number, was higher than AVILOO's result on 2, lower on 17 (within 1 point on 7 of them), with gaps from -2.4 to +0.7 points. So the dashboard figure is a guide, not proof.

The certificates read 95.0%–98.5% for 16 83.9 kWh cars and 96.0%–98.0% for 5 eDrive35 cars, all under 70,000 km. These are single cars for sale at one UK dealer, not averages.

Single AVILOO certificates published by a UK dealer (Car360) for cars it was selling. Every row is also on the i4 data page. See how to read a battery health certificate for the fields on a report.

Also see: general used-EV battery checklist · BMW i3 battery check · high-mileage used EVs · battery problem after buying: your rights (UK) · all models compared.

We are not paid by the battery-test providers mentioned on this page. Links marked "paid link" in the "Useful products and services" box are affiliate links. See our disclosure.

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